Anterior cervical foraminotomy for unilateral radicular disease.

STUDY DESIGN: A clinical series of patients with unilateral radiculopathy treated with the anterior cervical foraminotomy procedure. OBJECTIVE: To establish procedural techniques and clinical and radiologic outcomes for the anterior cervical foraminotomy procedure. SUMMARY OF BACKGROUND DATA: Cervical radiculopathy is typically caused by unilateral disc herniation or uncovertebral osteophytes that compress the ventral aspect of the nerve. Direct removal of a cervical lesion causing radicular symptoms without concomitant fusion seems to be an ideal treatment in selected patients. The indications for an anterior cervical neural foraminotomy are limited to unilateral radicular symptoms at one or two levels, with minimal neck pain. METHODS: Twenty-one patients were treated with the anterior cervical neural foraminotomy procedure during a 3-year period with follow-up from 6 to 36 months. There were 13 men and 8 women (age range, 27-58 years). Fourteen patients had symptomatic soft disc herniation, and 7 had uncovertebral osteophytes confirmed by magnetic resonance imaging and/or myelogram and computed tomography. Sixteen patients had a single anterior cervical neural foraminotomy, and 5 had procedures at adjacent levels. RESULTS: Nineteen patients (91%) had improved or resolved radicular symptoms, and 2 (9%) had persistent radicular symptoms necessitating further surgery (one two-level anterior cervical neural discectomy and fusion and one posterior foraminal decompression). CONCLUSIONS: Patients treated with the anterior cervical neural foraminotomy procedure have equivalent or better outcomes than those who undergo current cervical procedures. It appears to be a good alternative procedure for carefully selected patients with unilateral cervical radiculopathy and avoids a fusion of the disc space.

Cerebral arterial spasm after penetrating craniocerebral gunshot wounds: transcranial Doppler and cerebral blood flow findings.

OBJECTIVE: The goals of the study were to determine the incidence and time course of cerebral arterial spasm in patients with penetrating craniocerebral gunshot wounds, to study the relationship between vasospasm and subarachnoid hemorrhage (SAH) in these patients, and to evaluate the effects of vasospasm on outcome. METHODS: Thirty-three patients with craniocerebral gunshot wounds underwent computed tomography at admission and then underwent transcranial doppler ultrasonography (TCD). Velocities in the middle cerebral artery and the extracranial internal carotid artery were measured. Vasospasm was defined as a middle cerebral artery velocity greater than 120 cm per second and a hemispheric index (ratio of middle cerebral artery to internal carotid artery velocity) greater than 3. Intravenous xenon-133 cerebral blood flow (CBF) studies were performed for 10 patients. RESULTS: TCD was initiated, on average, 1.1 days after injury; 205 studies (mean, 6.3 studies/patient) were performed 0 to 33 days after injury. TCD showed vasospasm in 14 patients (42.4%). Xenon-133 studies performed within 24 hours of TCD measurements indicating spasm demonstrated normal or low CBF in three of five patients with spasm, ruling out hyperemia as the cause of elevated flow velocities in these three patients. Seven patients had unilateral vasospasm, and seven had bilateral spasm. Vasospasm was most prominent from Days 5 through 11. Vasospasm was distributed across all levels of injury severity, as defined by the Glasgow Coma Scale. Initial computed tomographic scans demonstrated SAH in all 14 patients with vasospasm but in only 9 of 19 without spasm (100 versus 47%, P < 0.0001, binomial distribution probability test). Outcomes for patients with vasospasm were slightly worse than for those without spasm (35.7 versus 47.4% good outcomes, respectively); however, this difference did not reach statistical significance (P = 0.12). CONCLUSION: These findings demonstrate that delayed cerebral arterial spasm is a frequent complication in patients with craniocerebral gunshot wounds and is strongly associated with SAH. The frequency, time course, and severity of spasm are comparable with those observed with aneurysmal SAH and traumatic SAH caused by closed head injury. This study offers new insights into the hemodynamic pathophysiology after gunshot wounds to the brain and suggests that increased vigilance for vasospasm may be of benefit.

Cerebral blood flow as a predictor of outcome following traumatic brain injury.

As part of a prospective study of the cerebrovascular effects of head injury, 54 moderate and severely injured patients underwent 184 133Xe-cerebral blood flow (CBF) studies to determine the relationship between the period of maximum blood flow and outcome. The lowest blood flows were observed on the day of injury (Day 0) and the highest CBFs were documented on postinjury Days 1 to 5. Patients were divided into three groups based on CBF values obtained during this period of maximum flow: Group 1 (seven patients), CBF less than 33 ml/100 g/minute on all determinations; Group 2 (13 patients), CBF both less than and greater than or equal to 33 ml/100 g/minute; and Group 3 (34 patients), CBF greater than or equal to 33 ml/100 g/minute on all measurements. For Groups 1, 2, and 3, mean CBF during Days 1 to 5 postinjury was 25.7 +/- 4, 36.5 +/- 4.2, and 49.4 +/- 9.3 ml/100 g/minute, respectively, and PaCO2 at the time of the CBF study was 31.4 +/- 6, 32.7 +/- 2.9, and 33.4 +/- 4.7 mm Hg, respectively. There were significant differences across Groups 1, 2, and 3 regarding mean age, percentage of individuals younger than 35 years of age (42.9%, 23.1%, and 76.5%, respectively), incidence of patients requiring evacuation of intradural hematomas (57.1%, 38.5%, and 17.6%, respectively) and incidence of abnormal pupils (57.1%, 61.5%, and 32.4%, respectively). Favorable neurological outcome at 6 months postinjury in Groups 1, 2, and 3 was 0%, 46.2%, and 58.8%, respectively (p < 0.05). Further analysis of patients in Group 3 revealed that of 14 with poor outcomes, six had one or more episodes of hyperemia-associated intracranial hypertension (simultaneous CBF > 55 ml/100 g/minute and ICP > 20 mm Hg). These six patients were unique in having the highest CBFs for postinjury Days 1 to 5 (mean 59.8 ml/100 g/minute) and the most severe degree of intracranial hypertension and reduced cerebral perfusion pressure (p < 0.0001). These results indicate that a phasic elevation in CBF acutely after head injury is a necessary condition for achieving functional recovery. It is postulated that for the majority of patients, this rise in blood flow results from an increase in metabolic demands in the setting of intact vasoreactivity. In a minority of individuals, however, the constellation of supranormal CBF, severe intracranial hypertension, and poor outcome indicates a state of grossly impaired vasoreactivity with uncoupling between blood flow and metabolism.

Cerebral hemodynamic disturbances following penetrating craniocerebral injury and their influence on outcome.

Available data on the subject of cerebrovascular dynamics after penetrating craniocerebral injury and their effect on outcome were reviewed. Following penetrating injury, CBF is depressed, as is cerebral metabolism. This decreased flow likely is associated with poor outcome as previously shown in closed head injuries. A phenomenon interrelated with a decreased blood flow is posttraumatic vasospasm. Vasospasm occurs in a significant percentage of patients as demonstrated both by TCD and angiography, and there is a strong relationship with SAH. Vasospasm following penetrating injury has an onset and time course similar to that seen in both closed head injury and aneurysmal SAH. Vasospasm following penetrating craniocerebral injury may be a cause of secondary ischemic injury, but further study is needed before the prognostic significance of this phenomenon is defined. For now, drawing a parallel with closed head injury and aneurysmal SAH, it can be inferred that vasospasm following cranial gunshot wound may be an important pathophysiologic factor. Because interventions are available to combat vasospasm, including medications (e.g., nimodipine), volume expansion, and elevation of blood pressure, the authors believe that identification and treatment of this potentially damaging condition are compelling, especially in patients whose CT scans demonstrate SAH.

Analysis of brain tumors using 1H magnetic resonance spectroscopy.

BACKGROUND: Magnetic resonance imaging (MRI) is superior in delineating anatomic and pathologic information and has subsequently been married to the ability of magnetic resonance spectroscopy (MRS) to provide insight into the biochemical changes underlying pathology. Proton magnetic resonance spectroscopy (1H MRS) allows the non-invasive in vivo collection and measurement of chemical information from a selected volume of tissue (voxel). METHODS: We conducted a prospective trial in 23 patients with brain mass lesions and 16 normal subjects using proton magnetic resonance spectroscopy (1H MRS). The spectra were analyzed for N-acetyl-aspartate (NAA), choline compounds (Cho), creatine (Cr), and lactate (Lac). The ratios of the compounds in tumors were compared to normals. RESULTS: The tumors showed significant decreases in the mean peak height ratios of NAA/Cho, NAA/Cr, and significant increases in Cho/Cr when compared to tissue from normal subjects. Cho was elevated in all of the meningiomas and gliomas. In benign tumors, Cho was usually elevated while in metastases Cho was often normal or decreased. The four metastatic tumors showed NAA/Cho, NAA/Cr, and Cho/Cr that were similar to controls. Lac varied with tumor type and was elevated in many malignant primary brain tumors. CONCLUSIONS: 1H MRS is a powerful tool for safe, noninvasive analysis of tissue chemistry in vivo. Analysis of intracranial tumors reveals significant trends that might eventually be used in the classification of tumor histology and evaluation of the efficacy of tumor treatment.

Intensive care of patients with spinal trauma.

This article takes a systematic approach to intensive care unit management of acute spinal cord injury. Pathophysiology and current medical management of the neurologic injury are discussed. Anticipation, prevention, and treatment of sequelae of spinal cord injury are stressed in sections on respiratory, cardiovascular, venous thrombosis, and gastrointestinal issues, as well as in sections on nutritional, genitourinary, and skin problems associated with spinal cord injury.

Electromagnetic field focusing instrument augments resection of meningiomas.

The electromagnetic field focusing (EFF) surgical instrument creates an oscillating electromagnetic field that induces eddy currents in the tissue, which converge at the point of contact. This energy creates a focal spark capable of vaporizing tissue. The EFF instrument was used to resect 17 meningiomas in 14 patients. The effectiveness of the EFF probe in resecting tumor tissue was compared with that of the Cavetron ultrasonic surgical aspirator (Model 100) in 11 patients. The EFF system was superior to the Cavetron ultrasonic surgical aspirator in tumor excision in all but two cases, in which the EFF grounding tip was poorly tuned. Surgical time and blood loss were reduced by subjective analysis in all but these two cases, especially in the rubbery or calcified meningiomas resistant to aspiration. No complications were directly attributable to use of the EFF. Drawbacks encountered with the EFF system include buildup of "char" on the tip, requiring scraping, and intense heat at the tip, which occasionally melted the insulating sheath, requiring replacement.

In vivo metabolism of radiolabeled putrescine in gliomas: implications for positron emission tomography of brain tumors.

The in vivo uptake and metabolism of radiolabeled putrescine was examined in two glioma models: (a) the T9 gliosarcoma in the CD Fischer rat and (b) the U-87 MG human glioblastoma in the athymic (nude) mouse. Autoradiography after parenteral administration of [14C]putrescine revealed rapid and selective uptake by both tumors compared with normal brain. Polyamine analysis of the rat gliosarcoma demonstrated minimal conversion of labeled putrescine to its metabolites, spermidine and spermine, at 5 and 30 minutes after intravenous injection. The human glioblastoma also exhibited minimal polyamine conversion at 5 minutes, although there was a trend toward significant metabolism at longer time periods (30 and 45 minutes). In addition, the human glioblastoma produced nonpolyamine metabolites that suggest an alternative pathway of putrescine metabolism via gamma-aminobutyric acid. These in vivo findings are discussed in relation to the usefulness of putrescine as a marker for positron emission tomography of human gliomas.